Electric control system



Jan. 25, 1955 A, v. HUGHES ET AL ELECTRIC CONTROL SYSTEM 2 Sheets-Sheet 1 Filed April 18, 1946 INVENTORS flrzlzur l/ Hug/265 and Lawrence 5. Eademacfiez ATTORNEY 1955 A. v. HUGHES ETAL ELECTRIC CONTROL SYSTEM 2 Sheets-Sheet 2 Filed April 18, 1946 n'm of 0,0011% INVENTORS firf/lu? l/ Hay/res Q/Zd La zz/reizce 5. Bade/72461 2,.

ATTORNEY United Stats Patent ELECTRIC CONTROL SYSTEM Arthur V. Hughes and Lawrence B. Rademacher, Sharon,

Pa., assignors to the United States of America as represented by the Secretary of the Navy Application April 18, 1946, Serial No. 663,202

16 Claims. c1. 114-20 Our invention relates to electric systems of control for conveyances to be propelled through a fluid medium and, more particularly, to electric systems of control for et propelled torpedoes, also known as hydro-bombs.

Hydro-bombs may be launched from shore stations, surface ships, submarines, airplanes, etc. The most feasible method of launching is from an airplane. Our system of control is, therefore, herein discussed in conjunction with a method of launching from an airplane.

Since the jet propulsion motor is itself quite a dangerous implement, aside from the danger of the explosive charge, carried by the torpedo, elaborate safety precautions must be taken to make certain that the igniter for the jet propulsion motor is not accidentally fired.

One broad object of our invention is the provision of iafety features applicable toapparatus used on a hydroomb.

A more specific object of our invention is the provision of safety features that eflectively prevent firing of the igniter for the jet motor until the hydro-bomb strikes the water after launching from a plane.

Another object of our invention is the provision of arming means that are ineffective until the hydro-bomb, or torpedo, has traveled a given distance from its launching point.

The objects hereinbefore stated are merely illustrative. Other objects and advantages will become more apparent from a study of the following specification and the accompanying drawing, in which:

Figure l is a schematic showing of a hydro-bomb, or jet propelled torpedo, showing in a general way where in the hydro-bomb various elements for its operation are located;

Fig. 2 is a diagrammatic showing of certain portions of the electric control of the hydro-bomb;

Fig. 3 is a somewhat schematic showing of certain portions of the system of control as applicable to the exercise head of a hydro-bomb;

Fig. 4 is a showing of a pressure-operated switch for efiecting certain control functions of certain elements; and

Fig. 5 shows a pair of curves of utility in explaining the operation of certain elements of the control.

In Figure 1, HB represents the overall outline of the hydro-bomb provided with the rocket or jet motor JM, the steering control gyro G, the battery B, control panel CP, the paddle wheel propelled arming mechanism A, and the inertia trip firing mechanism I for the explosive charge located in the forward end of the hydro-bomb.

Since certain functions of a hydro-bomb must take place before the bomb is released from the suspension hooks, or shackle lugs, H, a pair of water-tight rubber plugs 4 and 25 are disposed in the housing wall and a vane operated water-tight starting switch 35 is also dis posed in the housing wall.

The steering gyro and the apparatus it controls do not constitute part of this invention, and are thus not shown in detail. To get an idea how the steering is effected, reference may be had to the copending application of Arthur V. Hughes, Serial No. 641,377, filed January 15, 1946, and entitled Electrical Control.

In Fig. 2, the elements there shown are all in the position they occupy, while the hydro-bomb is fastened in place on the launching rack by means of bomb shackles, or books, H, attached to the housing wall. The arrangement is such that the hydro-bomb is also prevented from moving angularly by any suitable means as for example by means of a pin on the plane fitting into I the recess R.

A better understanding of our invention may be had from a study of a typical sequence of operation of the system of control shown in Fig. 2. Let the assumption be that the hydro-bomb is suspended in a suitable rack on a launching plane. As soon as the plane is a given distance from the target, such as a ship, the pilot, or the bombardier on the plane, throws the plane switch 2 to its first position. In this position, a circuit is established from the positive terminal of the battery 1 through the plane switch 2, conductor 3, the rubber water-tight electric plug 4, conductor 5, back contacts 6 of the initial relay IR, the gyro motor GM, the back contacts 7 of the initial relay IR, conductor 8, plug 4, and conductor 9 to the negative terminal of the battery 1.

This circuit may be designated the ready circuit and the first position of switch 2 as the ready position. It should be noted at this point that the energization of the gyro motor brings the gyro wheel up to full speed in a matter of thirty seconds. Since the gyro is of the type driven by the motor during the entire run, and since the voltage of the battery 1 on the plane is chosen to have the same voltage, as for example twenty-four volts, as the portion of the battery B used for the gyro during the normal run of the hydro-bomb, there is thus no harm in running the gyro motor from the battery 1 as long as needed. There is thus no critical time set for the period between the closing of the ready circuit and the launching of the bomb.

As soon as the target appears in the proper position in the sighting equipment on the plane, and the target is roughly at the correct distance, the bombardier throws.

the switch 2 to the firing position, the second position.

When the switch 2 is in the firing position, a circuit is established from the battery 1 through switch 2, soleno1d 10 of the bomb releasing mechanism L to the negative terminal of the battery. Another circuit is established at the same instant. This circuit may be traced from the battery 1 through switch 2, conductor 11, plug 4, conductor 12, gyro solenoid 13, conductor 14, and plug 4 to the negatively energized conductor 9.

The energization of the gyro solenoid 13 operates the core type armature of this solenoid toward the right. This operation retracts the locking rod formed as an extension of one end of the armature. This end coacts with the latch 15 to lock the rod in the retracted position. Movement of the armature to the right also causes closing of contacts 16 and disengagement of clutch 18 whereby to uncage the gyro operated by the gyro motor GM. The gyro, by virtue of its characteristics, thus maintains its reference position after the opening of the clutch 16. The gyro thus assumes 'its steering control function.

The movement of the plane switch 2 to the firing position also causes the disconnection of the gyro motor GM from the battery 1. The closing of contacts 18 establlshes a circuit from the positive terminal of battery B, disposed in the hydro-bomb, through conductor 17, contacts 18, conductor 19, actuating coil 20 of the initial relay IR, contacts 22 of the timer T and conductor 23 to the negative terminal of the battery B. Since the actuat ng coil 21 of the stop relay ST is in parallel to the actuating coil 20, the initial relay IR and stop relay ST operate substantially simultaneously.

The operation of the initial relay IR causes the opening of contacts 6 and 7. This is a valuable feature. The events set in operation by the movement of the switch 2 to the firing position transpire with extreme rapidity. An instant after the operation of the elements 13, 15, 16 and 18, the hydro-bomb is dropping from the plane since the launchlng mechanism L has also operated. The upper portion of the plug 4 is thus pulled free of the lower portion fixed in the torpedo shell and all circuits at plug 4 are interrupted. Since the terminals of conductors 5 and 8 are, when the torpedo strikes the water, exposed to sea water which may short these conductors, the continued The conductors as 3, 9. and 11 may be used to pull the upper portion of the plug 4 from the lower portion, but preferably a lanyard 24 connected to the upper portion of plug 4 and secured to some suitable portion of the plane structure is used to pull the plug To prevent the possibility of the operation of the jet motor igniter 44 before such operation should take place, we Providethe igniter 4.4. with a shorting. plug 25. Any potential applied to leads, as. conductors 43 and 44- from any cause will thus be. prevented from operating the igniter. The plug 25 is secured to a lanyardas 26, fixed to the plane for opening the igniter short as the plug 25 as soon as the hydro-bomb is a given distance from the launching'plane.

Since. certain circuits should not be established before the torpedo strikes the water, we provide a water trip switch 35. having an actuating vane. This vane is .held in the position shown by the detent block 27 disposed back of. the vane and by a, frangible wire 29' secured to the vane and torpedo shell. The detent block 27 is, after the torpedo has dropped a given distance from the plane, moved. away from the vane by the lanyard 28 secured to the detent block and the plane structure. The water trip switch is so designed that the force of the air on the vane of the water trip switch is insufficient to operate this switch, regardless of whether the wire 29 is present or not. The wire 29 is, however, an added safety feature. On. striking the water, the vane breaks the wire 29, and the switch is thus operated.

The water trip switch is shown rather schematic in this disclosure since per se it forms no part of this invention. A more comprehensive disclosure of this switch may be found in our copcnding application to Arthur V. Hughes. and Lawrence B. Rademacher, Serial No. 663,204, filed April 18, 1946, and entitled Water Trip Switch; now U. S. Patent 2,589,547.

The operation hereinbefore mentioned of the initial relay IR also causes the closing of contacts 32 and 33 and the operation of the stop relay ST causes the closing of contacts 34 and- 39. One circuit is thus established from the twenty-four volt junction 30 of the battery B through conductor 31, contacts 32 of the initial. relay Il'R, gyro motor GM, contacts 33 of the initial relay 1R, contacts 34 of the stop relay ST, and conductor 23'tothe negative terminal of the battery B.

It isthus apparent that the gyro motor GM is in operation as the torpedo falls through the air. Since the gyro was unlatched at the instantof release from the plane, the course of the torpedo in the water is made to follow thecourse of'the plane atthe instant of'release.

The instant the hydro-bomb strikes the water, the water trip switch 35 operates to close contacts 37 and contacts 41. This operation closes a circuit. from the positive terminal of the battery B through conductors 17 and 36, contacts 37, actuating coil 38 of the control relay TD, contacts '39 and 34-of the stop relay ST to the negative conductor 23. The closure of contacts .46ldoes not at this instant establish any circuit except to set up conditionsfor a circuit to be established later.

Operation of the control relay TD causes the closing of contacts 40 and 46. The closing ofv contacts 40 energizesthe timer motor 39. After a short adjustable time delay, the timer motor causes the closing of contacts 42 and 45. This short time delay is important. At the moment the hydro-bomb strikes the water, the bomb, which, of course, is moving with considerable velocity, is likely to moveviolently and with considerable irregularityabout the surface of the sea. Under such conditions of motion, it is not desirable to start the rather violently acting jet motor JM. Shortly after entering the water, the hydro-bomb becomes stabilized. The time delay mechanism T including the timing motor 39' and contacts 42, 22 and 60, has been only schematically illustrated and may compriseany conventional motor driven timing mechanism which is operativeto actuate a series of contactsat predetermined time intervals after operation of the mechanism has ben initiated as by energization of its motor.

The timer motor is adjusted'to close contacts 42 and 45 after a time interval long enough to allow stabilization of the hydro-bomb movement. A circuit is immediately established from the positively energized conductor 36 through contacts 41 of the water'trip switch, contacts 42 of the timer T; fuse 43, igniter;44, and contacts 45 and 46 to-the battery B. The igniter-fires the propulsionmaterial in the jet motor and as a result hot gases begin to issue at tremendous velocity from the nozzle 47 of the jet motor JM. The torpedo is thus propelled through the water at the depth maintained by the depth control and in the direction determined by the steering gyro G.

From the discussion hereinbefore given, it is apparent that the igniter 44 can only be fired after the water trip starting switch 35 is closed. The detent block 27 and the frangible connection 29 prevent accidental or manual closing of the water trip switch. It is conceivable that after an exercise run someone may forget to open the water trip switch. To avoid any danger from this source the switch arm is made of sufiicient length that the burned-out motor can not easily be removed without the forward mounting ring 65 striking the switch arm to open the switch (see Fig. 1). Also it is difficult to load a new motor in the torpedo with the switch 35 closed.

However, if after a new motor is loaded in the torpedo the water trip switch should be closed then, assuming the torpedo battery voltage is available, the contacts of the control relay TD will close. However, the short'circuit across the igniter 44 at the plug 25 willby-passmost of the igniter circuit current allowing only a relatively'small' current to flow through the igniter 44. Nevertheless, unless heat is conducted away from the igniter faster than it is generated by the small current the igniter will reach a sufficiently high temperature after a long time to fire-the igniter. This contingency is avoided by means of the fuse 43 which carries the sum of the currents throughthe igniter 44 and through the short in the plug 25. The fuse 43 ruptures the current in the igniter circuit before the igniter can fire.

For normal operation it is, of course, apparent that the fuse 43 must be able to-carry the normal firing current of the igniter 44 without rupturing that current. Thistype of operation can be obtained by selecting a fuse which is properly coordinated with the rest of the elements in the igniter circuit. Both the igniter 44 and the fuse 43 have current-time characteristics of the same general shape. Curve 43' represents the current time characteristic of the fuse 43 and curve 44' is a similar curve for the igniter 44. The igniter, however, must have a lower equivalent fuse rating than the fuse. 43 itself. The operation can be described with the aid ofthe curves shown in Fig. 5.

With the short circuit on the igniter 44 the current through the igniter can be represented as I1. The current through the fuse 43, however, is represented as Is. The fuse 43 will thus open before the igniter would fire at time 1. The fuse 43 fires at is. The margin of safety is thus a function of the difference between t3 and t1.

With theplug 25 removed-the igniter shortis removed. The current in the fuse 43 and igniter 44 is thus the same, say I 2. Under these conditions the igniter. 44 fires at time tz whereas the fuse 43, would not rupture the current until time t4. Hence the igniter circuit is safe against deliberate or any accidental. operation as long as theshort-circuit plug 25 is in place.

As the torpedo, or hydro-bomb, moves through the water, the arming mechanism A operates to arm the torpedo after it has moved through the water' a given distance. The arming mechanism A includes an element 48, housing an explosive squib 49, that is; moved vertically in proximityto the booster charge contained in theelement 50. After the element movesthe desired distance vertically, an arming set-up circuit is made at 51through the explosive squib 49.

As soon as the torpedo strikes-the target. the inertia switch I makes contact with the housing 52 consisting of-conducting material. The squib 49 is thus fired by the circuit from the positiveterminal of the battery B through the'circuit closed at 51 by housing. 48 of.squib 49, contact housing 52, inertia switch 53.and conductor 54 10 the-negative terminal-of the battery.

It should be noted that the. grounded short circuit conductors 55 prevent any premature operation of the squib 49 as might otherwise. possibly take place'because of leakage currents or static charges on terminals 48 and 51 and leads 49. The details of this arming mechanism, form no part of the presentinvention, but are disclosed in the copending application ofArthur V. Hughes,..Scrial No. 755,663, filed June 19, 1947, and, entitled Arming Mechanism,

If, for any. reason, the-torpedo should fail to. hittlie target, then, to guard against recovery of the torpedo by the enemy for study, provision is made for self destruction. At the end of the run, the propulsion material will burn to the bottom, or forward end, of the tank of the jet motor housing the material. In so doing, an explosive charge in the pressure switch 56 is ignited with the result that contacts 57 close to fire the squib 49. It will be noted that the squib 49 is fired even though the inertia switch 1 has not actuated.

If merely exercise runs are contemplated, then the forward end of the torpedo is empty of explosives and is provided with a ballast liquid and lead ballast blocks Lb so that the liquid and blocks are equivalent in weight to the explosive charge used for war shots. The arming mechanism A lacks a charge and is locked against operation, or may not even be in the torpedo. The preferred arrangement is to remove the warhead and substitute an exercise head having a discharge valve DV for discharging the ballast liquid at the end of an exercise run. To create the necessary pressure in the exercise head to blow the ballast liquid we utilize a flask 58 containing carbon dioxide, or some other gas, under high pressure. At the neck of the bottle we provide a fuse 59 for actuating the valve 62.

At or near the end of the run the timer closes its contacts 60 thereby closing a circuit for the fuse 59, as shown. This fuse opens the valve 62 whereupon the high pressure gas in the bottle 58 is admitted to the exercise head and the ballast liquid is discharged through the discharge valve.

While we have hereinbefore disclosed how the ballast liquid may be expelled at the end of an exercise run by a circuit set up by the timer T, the pressure responsive switch shown in Fig. 4 may be used for the same purpose. The circuit for this operation is shown in Fig. 3.

The pressure switch comprises a metal tube 70 threaded into the junction 71 hermetically welded into the forward end of the jet motor IM. The aft end of the tube 70 extends into the combustible material in the jet motor so that when the material burns down so that the combustion takes place about the tube 70 the small amount of explosive material 72 is ignited and its hot gases expand into the diaphragm chamber 73. The diaphragm 74 carries the contact bridging element 75. This element closes the contacts 57 to effect either the self destruction of the torpedo, as is apparent from the discussion of Fig. 2, or the blowing of the ballast liquid from the exercise head.

If the use is of the nature shown in Fig. 3 then the contacts 57 close the circuit for the fuse in the valve 62. The compressed gas in the flask 58 thus enters the exercise head blowing the ballast liquid out of the head at the discharge valve 76.

While we have shown and described but one embodiment of our system of control with some variations, we do not wish to be limited to the exact showing herein made but wish to be limited only by the scope of the claims hereto appended.

We claim as our invention:

1. In a system of control for a torpedo of the rocket propelled type for launching from a supporting structure on a launching plane, in combination, a source of electric energy in the torpedo, a rocket motor, an electric igniter for starting the rocket motor, a relatively low resistance shunt circuit for the igniter, said shunt circuit being disposed in a removable electric plug so that the shunt circuit for the igniter may be removed by removal of the plug, a lead at one end connected to one of the connected terminals of the igniter and shunt circuit, a second lead at one end connected to the other of the other connected terminals of the igniter and shunt circuit, a fuse having a longer current time rating that the igniter disposed in one of said leads, an electric time limit device, a time limit switch operable by said time limit device disposed in one of said leads, an electromagnetically operable contactor in series with said switch, the arrangement being such that when both the contactor and switch have been operated one terminal of the igniter is connected to one terminal of said source of electric energy, a second time limit switch operable by said time limit device disposed in the other of said leads, a water trip device including a switch in series with said second time limit switch, the arrangement being such that when both the switch actuated by the water trip device and the second time limit switch are closed the igniter is connected to the other terminal of said source of electric energy to thus start the rocket motor, said water trip device including a second switch for energizing the electromagnetically operated contactor, means responsive to the operation of the electromagnetically operable contactor for energizing said time limit device whereby the time limit switches are operated a given time after said water trip device is operated.

2. In an electric system of control fora torpedo launched from a launching structure, in combination, a control gyro having a driving motor in the torpedo, an electric plug having two terminals, a starting circuit connecting one terminal of the driving motor to one terminal of the plug, a second starting circuit connecting the other terminal of the driving motor to the other terminal of the plug, a removable mating plug having a pair of terminals, said mating plug being secured to the launching structure so that said plugs are disengaged by the launching operation, a supply of electric energy on the launching structure, switching means on the launching structure for connecting the terminals of the mating plug to the source of electric energy on the launching structure to thus cause operation of the gyro driving motor, a source of electric energy on the torpedo, and switching means on the torpedo for opening the starting circuits and connecting the driving motor to the source of electric energy on the torpedo.

3. In an electric system of control for a torpedo launched from a launching structure, in combination, a control gyro in the torpedo, a driving motor therefor, means including a source of electric energy disposed on the launching structure and a starting circuit leading from said source of electric energy through the torpedo shell to the driving motor, means responsiveto manipulations made outside of the torpedo for closing said starting circuit, a source of electric energy in the torpedo, a running circuit leading from the source of electric energy in the torpedo to the driving motor, and switching means in the torpedo set in operation by the launching operation for interrupting the starting circuit inside the tor pedo and for closing the running circuit to energize the driving motor from the source of electric energy in the torpedo.

4. In an electric system of control for a torpedo launched from a launching structure, in combination, a control gyro in the torpedo, a driving motor therefor, means including a source of electric energy disposed on the launching structure and a starting circuit leading from said source of electric energy through the torpedo shell to the driving motor, means responsive to manipulations made outside of the torpedo for closing said starting circuit, a source of electric energy in the torpedo, a propulsion motor for the torpedo, a running circuit leading from the source of electric energy in the torpedo to the driving motor, and switching means in the torpedo set in operation by the launching operation for interrupting the starting circuit inside the torpedo and for closing the running circuit to energize the driving motor 1 from the source of electric energy in the torpedo, and

time limit means set in operation by the torpedo striking the water for starting the propulsion motor a relatively short time interval thereafter.

5. In an electric system of control for a torpedo,

:- launched from a launching structure, in combination, a

control gyro in the torpedo, means for unlatching the gyro from the torpedo, a driving motor therefor, means including a source of electric energy disposed on the launching structure and a starting circuit leading from said source of electric energy through the torpedo shell to the driving motor, means responsive to manipulations made outside of the torpedo for closing said starting circuit, a source of electric energy in the torpedo, a running circuit leading from the source of electric energy in the torpedo to the driving motor, means set in operation by the launching operation for causing operation of the gyro unlatching means, and switching means in the torpedo set in operation by the launching operation for interrupting the starting circuit inside the torpedo and for closing the running circuit to energize the driving launching structure and a starting circuit leading from said source of electric energy through the torpedo' shell to the-driving motor, means responsive to manipulations made outsideof the" torpedo for closing said' starting circuit, a source of electric energy in the torpedo, a propulsion motor for the'torpedo, a running circuit leading from the source of electric energy in the torpedo to the driving motor, means set in operation by the launching operation for causing the operation of the gyro unlatching means, and switching means in the torpedo set in operation by the launchingoperationfor interrupting the starting circuit inside the torpedo and for closing the running circuit to energize the driving motor from the source of electric energy in the torpedo, and time limit means set in operation by the torpedo striking the water for starting the propulsion motor a relatively short time interval thereafter.

7. In a system of control fora conveyance of the rocket propelled type for launching from a support; in combination, an electric igniter for the rocket propulsion system of the conveyance, a firing circuit for the igniter including a source of electrical energy and a pair of leads connected to the igniter terminals, 21 relatively'lowresistance shunt removably connected in electrical parallel with the igniter, and a fuze serially connected in one of said leads.

8. In a system of control for a conveyance of the rocket propelled type for launching from a support; in combination, an electric igniter for the rocket propulsion system of the conveyance, a firing circuit for the igniter including a source of electrical energy and a pair of leads connected to the igniter terminals, a relatively low resistance shunt removably connected in electrical parallel with the igniter, and a fuze serially connected in one of said leads, means operable after the conveyance is launched from the support for removing said shunt, said firing circuitfurther including switch means operable in one position to disconnect the energy source from the igniter and in another position to connect the energy source to the igniter.

9'. In a system of control for a conveyance of the rocket propelled type for launching from a support; in combination, an electric igniter for the rocket propulsion system of the conveyance, a firing circuit for the igniter including a source of electrical energy and a pair of leads connected to the igniter terminals, a relatively low resistance shunt removably connected in electrical parallel with the igniter, and a fuze serially connected in one of said leads, and means connected to the support and to the shunt for removing the shunt after the conveyance has moved a given distance from the support after launching of the conveyance.

10. In a system of control for a conveyance of the rocket propelled type for launching into the sea from a support; in combination, an electric igniter for the rocket propulsion system of the conveyance, a firing circuit for the igniter including a source of electrical energy and a pair of leads connected to the igniter terminals, a relatively low resistance shunt removably connected in electrical parallel with the igniter and a fuze serially connected in one of said leads, and means connected to the support and to the shunt for removing the shunt after the conveyance has moved a given distance from the support after launching of the conveyance, said firing circuit further including time delay switch means having an open position wherein the circuit between the energy source and the igniter is broken and a'closed position, said switch means being normally open. and means operable upon the conveyance entering the sea for eflecting operation of said switch means to its closed position.

11. In a system of control for a conveyance of the rocket propelled type for launching from a support; in combination, an igniter for starting the rocket propulsion system of the conveyance, a source of electrical energv, a relatively low resistance shunt removably connected across the igniter terminals, means operable after launching of the conveyance for removing said shunt, and an electrical circuit from. the energy source to the igniter including switching means normally operable after removal ofthe shunt for connecting the igniter tov the energy S0urce.

12. In a system of control for a torpedo of the jet propelled type for launching into the sea from a support; in combination, an electric igniter for the jet propulsion system of the torpedo, a source of electrical energy, a relatively low resistance shunt across the igniter terminals, a lanyard secured to the shunt and' to the support whereby the shunt is removed when the torpedo has moved a given distance from the support, an electrical circuit from the energy source to the igniter including time delay switch means having an open position wherein said circuit is broken and'a closed position, said switch means being normally open, and means operable upon the torpedo entering the sea for etfectingoperation of said switch means to its closed position.

13. In a system of control fora torpedo of the rocket propelled type for launching into the sea from a suitable launching structure on an airplane; in combination, an electric igniter for the rocket propulsion system of the torpedo, a relatively low resistance shunt removably connected across the igniter terminals,v a lanyard connected at one end to the plane and at the other end to saidshunt for removing the shunt fromthe igniter when the torpedo has dropped a given distance from the plane, a source of electrical energy, an electrical circuit from the energy source to the igniter comprising switching means set in operation by the water as the torpedo enters the sea and including time delay means for electrically connecting the igniter to the energy source a relatively short time interval after the torpedo enters the sea to thus start the rocket propulsion system.

14. In an electric system of control for a torpedo to be launched from a support; in combination, a control gyro including a gyro drive motor in the torpedo, said motor having a pair of terminals, a pair of energizing circuits for the motor, one of said circuits including a source of electrical energy on the support and a separable electrical connection having one part fixed tothe support and another part fixed to the torpedo, and the other of said circuits including a source of electrical energy in the torpedo, and means including switch means on the support and a relay in the torpedo operable in one position of said switch means to connect the gyro drive motor to said one circuit and in another position of said switch means to open said one circuit and electrically isolate the gyro drive motor from said separable electrical connection and connect the gyro drive motor to the other of said circuits.

1.5. In an electric system of control for a torpedo to be launched from a lunching structure; in combination, a control gyro in the torpedo, a driving motor therefore, means including a first source of electricaljenergy outside of the torpedo and an electrical circuit from said source to the motor for energizing said motor. by manipulations made on the outside of the torpedo, a second source of electrical energy within the torpedo, and means for electrically isolating the driving motor from said circuit and for connecting said motor to said second source of electrical energy.

16. In an electric system of. control for a torpedo to be launched into the sea from a launching structure; in combination, a control gyro, a driving motor therefore, starting and running circuits for said motor, said starting circuit including means partially outside of the.

torpedo for effecting connection of the motor to said starting circuit, and means for disconnecting the motor from said starting circuit and for connecting the motor to said running circuit.

References Cited in-the file of this patent UNlTED STATES PATENTS 1,266,103 Chandler May 14, 1918 1,402,746 Dieter Jan. 10, 1922 1,792,937 Sperry Feb. 17, 1931 1,814,152 Harrison July 14, 1931 

